Oil compositions containing rust inhibitors



3,004,917 Patented Oct. 17,- 1961 3,004,917 OIL COMPOSITIONS CONTAINING RUST INHIBITORS Jean A. Fefer, Metuchen, NJ., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed May 14, 1959, Ser. No. 813,060

5 Claims. (Cl. 252-334) This invention relates to a combination of alkaline oxyalkylene glycols as rust inhibitors. The invention also relates to lubricating oil compositions containing said sulfonates and said esters in a synergistic rust-inhibiting combination.

While the additives of the invention are broadly applicable for rust prevention, they are particularly useful in crankcase oils. internal combustion engines usually require a rust inhibitor in order to prevent rusting by Water either drawn into the engine in the form ofhumid air or else formed directly in the engine as a combustion product. Also such inhibitors are necessary to prevent rusting by corrosive acids formed as a degradation product of the lubricating oil or the fuel. To be most effective and economical, it is desired that as small a proportion as possible of rust inhibitor be used. And it is particularly desirable that the rust inhibiting material contribute other desirable additive properties to the oil. In the past, alkaline earth metal sulfonates were frequent additives for crankcase lubricants. These materials notonly serve as rust inhibitors, but they also acted as detergent additives. It has now been found that these alkaline earth sulfonates can be greatly enhanced in their rust preventing properties by the presence of a fatty acid diester of a polyglycol. wards improving detergency and sludge'dispersancy of the oil. I 4

While primarily designed for use in lubricating oils, the synergistic combination of the invention may be used in various rust preventive and cutting oils as well as in patents, e.g., US. 2,467,176. The sulfonates can also be derived from relatively pure alkyl aryl sulfonic acids having from about 10 to 33 carbon atoms per molecule. For example, sulfonated products of alkylated aromatics such as benzene, toluene, xylene, etc., alkylated with olefins or olefin polymers of the type of polypropylene, polyisobutylene, etc. can be used. Specific examples of sulfonates which are used as additives include: petroleum sulfonates such as calcium petroleum sulfonate and barium petroleum sulfonate; and synthetic sulfonates I such as calcium di-Cg alkyl benzene sulfonate, barium di-C alkyl benzene sulfonate and calcium C alkyl benzene sulfonate, wherein said C alkyl group isderived from diisobutylene; said C group is obtained from tripropylene and said C group is obtained from tetraisobutylene. V i r The above sulfonates may be either neutral sulfonates, i;e. where the sulfonic acid is neutralized with an equal mole equivalent amount of metal base, or the sulfonates may be of the so-called high alkalinity type. In the latter case, additional metal .base, in excess of that required for simple neutralization, is reacted with the sulv United States Patent cc I earth metal sulfonates and fatty acid diesters of poly- 10 Thus, crankcase lubricating oils for In addition, the diesters alsocontribute to- 35 7 form a substantially neutral final product.

fonate to form an alkaline product which can then be blown with carbon dioxide to reduce its alkalinity and Recent work has indicated that suchso-called high alkalinity .sulfonates are nothing more than dispersions of, neutral sulfonates and a carbonate of the metal used which arebelieved to exist in the form of colloidal sols; In any event, the term sulfonate as used herein and in the appended claims includes both neutral sul-fonates and so-called high alkalinity sulfonates.

One sul-fonate that was used in several of the working examples of the invention and. which is very effective, is available under the trade name of NA-SUL-BSN. This product consists of 50 wt. percent light'mineral oil and 50 wt. percent of a neutral barium dinonylnaphthalene sulfonate of the type described in U.S. Patent No. 2,7 64,-

5w r""ihematerials desefibed in t ms patent ineiude sal such as magnesium, barium and calcium salts of a dinony-lnaphthalene sulfonic acid, the nonyl-radicals of which are highly branched and-preferably have a tertiary carbon atom. Such sulfonates can beprepared as' follows: Naphthalene is alkylated with highly branched nonenes, e.g. tripropylene in the presence of a suitable catalyst such as hydrogen fluoride or-anhydrous aluminum chloride in an anhydrous solvent such as naphtha. The resulting dinonylnaphthalene dissolved in a solvent which is free of aromatics or olefins, is then sulfonated with concentrated sulfuric acid, e.g. oleumc The sulfonated product is then washed with alkaline water, and the solvent layer containing the water-insoluble sulfonic acid is then allowed to stratify and the water is drawn off. This procedure may be repeated several times to give a relatively pure product consisting of the sulfonic acid in the hydrocarbon solvent. The sulfonic acid can then be neutralized with a metal base to form the salt.

A high alkalinity barium synthetic sulfonate was used in several working examples of the invention'in the form of a mineral oil solution containing 43 wt. percent of the sulfonate. The sulfonate had a barium content of about 14 wt'percent, based on the weight of sulfonate. The sulfonic acid portion of the sulfonate was prepared by alkylating benzene with polypropylene, said sulfonic acid portion having an average molecular weight of about 440 of which wt. percent of the sulfonic acid radicals had a molecular weight greater than 400. This sulfonate was prepared by reacting neutral barium sulfonate with additional barium hydroxide followed by neutralizing by bubbling carbon dioxide through the sulfonate.

The esters operable in the invention may be represented by the general formula:

RCO (OR' OOCR wherein each R is an aliphatic hydrocarbon radical or hydrocarbon radical interlinked by l to 3 ester linkages. These hydrocarbon radicals may contain 12 to 30, pref erably 16 to 22 carbon atoms and may be saturated or unsaturated, branched or straight chain or hydroxy substituted md can be the hydrocarbon radicals of fatty acids. R is an aliphatic saturated hydrocarbon radical containing 2 to 4carbon atoms and n has a value of 3 to 20, preferably 4 to 9. Esters of the above type are readily prepared by esterification reactions between poly- 65 .glycols such as polyethylene glycol, polypropylene glycol,

polybutylene glycol and a fatty acid such as myristic acid, palmitic acid, stearic acid, oleic acid, arachidic acid, behenic acid, hydroxy acids such as 12-hydroxy stearic acid,

'as well as dimer and trimer esters of hydroxy fatty; acids or unsaturated-fatty acids, e.g. dilinoleic acid, triricinoleic acid, etc. One specific material of the above type is a polyethylene glycol dioleate having a molecular weight of about 750 and available under the trade name of Nonisol 210. This particular material was used in several of the working examples of the invention. Another specific ester used in the working examples is polyethylene glycol 400 di(tri-ricinoleate) which has a total molecular weight of about 2 000. This material is formed by esterifying polyethylene glycol 400 (having an average molecular weight of about 400) with two molar proportions of the trimer of ricinoleic acid formed by condensation of =ricinoleic acid with itself.

The base oil to which the additives may be added, will preferably be a mineral lubricating oil, although various synthetic oils may be used. Examples of such synthetic oils include various monoesters, diesters, complex ester, silicones and polysilicones, carbonates, mercaptals, formals andother synthetic lubricating oils known to the art.

The compositions of the invention will contain about 1 to'ZO, preferably 1 to parts by weight of the sulfonate per one part by weight of glycol ester. This additive mixture can be used in lubricating oils in amounts of about 0.05 to 5.0, preferably'OJ to 1.0 wt. percent based on the weight of the finished oil composition. Also oil concentrates containing 5.0 to 40.0 wt. percent of the additive mixture maybe prepared.

Various other additives may also be present in the composition in amounts of 0.1 to 10.0 wt. percent, based on the total weight of the finished composition. For example, in crankcase lubricating oils, it is usual to have polymers such as polyisobutylene, polymethacrylates, copolymers of alkyl fumarates with vinyl acetate and various other long chain polymers usually having molecular weight of about 5,000 to 25,000 as viscosity index improvers and pour point depressants. Oxidation inhibitors are also frequently used in such compositions, such as phenyl a-naphthylamine as well as various detergent additives such as metal salts of alkyl phenol sulfides, complexes of various P 8 treated hydrocarbons neutralized with metal bases or metal salts of other materials such as phenols, sulfonates, carbonates, .etc.

wt. percent of a detergent inhibitor, which consisted of a P 8 treated polybutene neutralized with barium alkyl phenate and barium sulfonate, and finally an antioxidant of the zinc dialkyl dithiophosphate type. This fully compounded crankcase oil had a viscosity of about 69 SUS at 210 F. and a V1. of about 140. The resulting compositions were subjected to a series of three laboratory tests for rusting. These tests were carried out as follows:

Hydrobromic acid test (HBr test) In this test, clean sandblasted steel panels were first dipped in a 0.1% hydrobromic acid aqueous solution and allowed to drain, followed by dipping into the oil composition to be tested. The panels were then stored in an upright position and were examined after 4 hours and evaluated. This test determines the eifectiveness of inhibitors in a weak acidic environment as might be encountered in a crankcase oil during use and in general is regarded as a very severe test.

Humidity cabinet test This test was carried out in accordance with the JAN- H-792 procedure and involves dipping clean steel sandblasted panels into the oil composition and suspending the composition in a humidity cabinet: maintained at 120 F., and 100% relative humidity. The panels are periodically examined and :the number of hours upto the first specks ofrust is determined.

ASTM (distilled water) rust test TABLE I.LABORAT.ORY BENCH TEST RESULTS Humidity ASTM Run Rust Inhibiting Additive (wt. percent) HBr Test Cabinet Rust .Test Life (Scale No.) (hours) A None Heagy rust on.100% surface o Very light rust on 100% surfac Heavy'rust on 100% surface }Very light rust on.100% surface 0.2% Nonisol 210 H 1.0% Nonisol 210. I 1.0% Barium Sulfonate Solution J 0.5% Nonisol 210 0.5% Barium Sulfonate Solution.

1 Oil solution containing 43 w 9 100% polyethylene glycol dl The invention will be further understood by the following examples:

EXAMPLE I t. percent barium high alkalinity sulfonate. I

oleate. 8 Oil solution containing wt. percent or neutral barium dlnonylnaphthalene sulionate.

As seen by the preceding table, the combination of sulfonate and the glycol diester were considerably more effective, particularly in an acid environment as measured by the hydrobromic acid test, than were either of the materials alone.

EXAMPLE II In order to further test the performance of the compositions in actual use,-a=*Buick rust testwas carried out. In

this test a' Buick engine-was equipped with polished pushrods and two polished steel spindles. One-spindle was placed in the pushrod "chamber above the oil level and the other spindle was suspended under the left rocker shaft. The cylinder walls were burnished before the test and a new set of hydraulic valve lifters were used for each test. This engine was run for a total of 144 hours on a cycle'of 3 hours running, followed by 3 hours off. When running, air of about 80 grains of water per pound of dry air absolute humidity was fed through the carburetor intake into the engine. At the end of the test, the engine was disassembled and the degree of actual rusting was determined on five areas of the engine. The compositions tested and the results obtained are summarized in the following table wherein percent indicates the percent of surface that was rusted and wherein the degree of rusting is indicated as very light (V. Lt.), light (LL) or medium (Med.).

TABLE II.ENGINE TEST RESULTS Polyethylene glycol (400 ave. mol. wt.) di(tri-ricinoleate).

Engine Ratings Run Rust Inhibiting Ad- Rocker Arm ditive (wt. percent) Covers Rocker Pushrod Pushrods Cyl. Walls Lifters Arm Chamber Spindle Spindle K None 1 841% Lt 70% Med 45% LL--- 71% Lt 80% Lt 55% Med. 0.3 Nonisol 210-- 16% Li; 93% Lt- 33% Lt.- 100% V. ML... 52% ML... 12% L12. M- gg g f i g }s% Lt 42% BL... 33% La-.- 55% Lt 20% LL... 18% Lt. N- 2 Ba Sulionate 5% Lt 75% LL...

1 Same base oil composition as was used in Example 1.

EXAMPLE III While the preceding tests have illustrated the effectiveness of the combination of the invention in a fully formulated premium crankcase lubricant, equally efiective results are obtained in the absence of other additives. Thus, a combination of a /2 wt. percent of the high alkalinity barium sulfonate previously described and /2 wt. percent of Nonisol 210 in a mineral lubricating oil having a viscosity of 45 SUS at 210 F., and a VI. of about 110 and containing no other additives, was superior to the same oil containing 1 wt. percent of either of the additives alone. This is demonstrated by the following table which summarized the compositions tested and the test results obtained:

The data in Table III shows that run No. R gave no rusting whatsoever in the ASTM rust test (Scale No. 1 equals no rust) and very light rust in the hydrobromic acid test. In comparison, however, the sulfonate alone and the ester alone were much less eifective.

EXAMPLE IV Equally eifective performance is obtained with other polyglycol esters. This is demonstrated in the following table, which gives results on the combination of NA-SUL-BSN sulfonate and a polyethylene glycol di(triricinoleate), both of which materials have been previously described in detail. These materials were tested in a mineral lubricating oil base having a viscosity of about 69 SUS at 210 F. and a V.I. of 140 which contained only the polyisobutylene and polymethylmethacrylate V1. improvers previously mentioned.

What is claimed is:

l. A lubricating oil composition comprising a major amount of lubricating oil and about 0.5 to 5.0 weight percent of a rust inhibiting combination of an oil soluble barium alkyl aryl sulfonate of sulfonic acid having a molecular weight of 200 to 600 selected from the group consisting of high alkalinity barium sulfonates and a neutral barium dinonyl naphthalene sulfonate; and a polyethylene glycol dioleate having from 3 to 20 ethylene glycol units and wherein the weight proportion of said sulfonate to said dioleate is about 1:1 to 5:1.

2. A lubricating oil composition according to claim 1 wherein said sulfonate is a neutral barium dinonylnaphthalene sulfonate.

3. A lubricating oil composition according to claim 1 wherein said sulfonate is a high alkalinity barium sulionate.

4. A lubricating oil composition according to claim 2 wherein the quantity of said rust inhibiting combination is about 0.1 to 1 wt. percent.

5. A lubricating oil composition according to claim 3 wherein the quantity of said rust inhibiting combination is about 0.1 to 1.0 wt. percent.

References Cited in the file of this patent UNITED STATES PATENTS 2,417,281 Wasson et a1. Mar. 11, 1947 2,614,982 Caldwell et a1 Oct. 21, 1952 2,614,983 Caldwell et a1. Oct. 21, 1952 2,638,446 Wasson May 12, .1953 2,648,643 Adams et al. Aug. 11, 1953 2,751,350 Peeler et al. June 19, 1956 2,764,548 King et a1 Sept. 25, 19516 2,824,836 Smith et a1. Feb. 25, 1958 2,850,455 Kern et al Sept. 2, 1958 2,882,227 Lindberg Apr. 14, 1959 FOREIGN PATENTS 740,807 Great Britain Nov. 23, 1955 

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR AMOUNT OF LUBRICATING OIL AND ABOUT 0.5 TO 5.0 WEIGHT PERCENT OF A RUST INHIBITING COMBINATION OF AN OIL SOLUBLE BARIUM ALKYL ARYL SULFONATE OF SULFONIC ACID HAVING A MOLECULAR WEIGHT OF 200 TO 600 SELECTED FROM THE GROUP CONSISTING OF HIGH ALKALINITY BARIUM SULFONATES AND A NEUTRAL BARIUM DINONYL NAPHTHALENE SULFONATE, AND A POLYETHYLENE GLYCOL DIOLEATE HAVING FROM 3 TO 20 ETHYLENE GLYCOL UNITS AND WHEREIN THE WEIGHT PROPORTION OF SAID SULFONATE TO SAID DIOLEATE IS ABOUT 1:1 TO 5:1. 